The computer field in general has been plagued by the introduction of programs known as computer “viruses”, “worms”, or “Trojan horses”. These programs are often introduced for malicious reasons, and often result in significant damage to both stored data and other software. Many software solutions have been devised to help counter this growing threat to computer file integrity. Among these solutions is a general virus scanner program that scans a file or set of files, for particular known viruses. This method of virus detection is particularly effective against known viruses.
Computer viruses have the particular property of being able to replicate themselves and thus spread from one computer file to another, one computer volume to another, and eventually, from one machine to another. The virus may not be designed to do anything intentionally malicious, but to qualify as a virus, it must have the capability of replicating itself. This distinguishes computer viruses from programs such as “Trojan horses”.
Viruses may spread in a number of ways. For example, a virus may spread by adding itself to code that already exists within some program on a computer, then changing that preexisting code in such a way that the newly added viral code will be executed. This will then enable the virus to execute again and replicate itself in yet another program.
With new classes of pervasive devices being connected to the Internet along with the use of enterprise servers, it is likely that viruses may be designed to infect these pervasive devices as well. These pervasive devices include personal digital assistants (PDAs), such as the Palm Pilot (available from Palm Computing, Inc.); analog and digital cellular phones; network-connected home appliances, such as certain refrigerators; automotive computers; screen phones that mix data communications with voice communications; and Web-enabled televisions that support interactive television programming, Web access, and personal communications. With the number of pervasive devices expected to surpass the current number of PC and laptop computers, the infection of pervasive devices with a virus would result in more devastating damage and be more difficult to disinfect. Protecting pervasive devices from exchanging viruses imposes new challenges due to the different connection styles of these pervasive devices. For example, many pervasive devices are only intermittently connected to the computer network. Moreover, these computers operate by exchanging data updates with a server, a process called synchronization, to ensure that the data store on the device and the data store on the server (a synchronization server) are kept consistent. The task of protecting pervasive devices is made more complex because these devices typically have limited processor and memory resources. Consequently, these devices cannot run sophisticated virus scanning and correction programs, which invariably require considerable processor and memory resources on the machine being scanned.
Therefore, it would be advantageous to have an improved method and apparatus for protecting pervasive devices and servers from exchanging viruses.